1. Technical Field
Exemplary embodiments of the present disclosure relates to a method for manufacturing biochips and a biochip manufactured by the method, and more particularly, to a method for manufacturing a biochip having improved fluorescent signal sensing properties which can provide a location-based multi-sensing function and be applied to a real-time quantitative PCR (polymer chain reaction), and a biochip manufactured by the manufacturing method.
2. Related Art
Generally, a biochip is formed by regularly arranging reference samples including biological material such as DNA or proteins on a substrate made of material such as glass, metal such as gold, or nylon.
The biochip basically uses biochemical reactions between the reference sample fixed to the substrate and a target sample. Representative examples of the biochemical reaction between the reference sample and the target sample include the complementary binding of DNA bases, an antigen-antibody immune reaction and so forth.
Optical-based quantitative and qualitative diagnosis using the biochip is generally performed by detecting the degree of a biochemical reaction between the reference sample and the target sample through a process in which a result product of the biochemical reaction is converted into detectable light. Optical conversion media which are generally used are based on color formation, chemiluminescence, fluorescence, etc. resulting from chemical combination.
FIG. 1 is a view illustrating a conventional fluorescent reaction detection system.
Referring to FIG. 1, the conventional fluorescent reaction detection system includes a light source 10, a band-pass filter 20, a biochemical reaction device 30, a fluorescent band-pass filter 40 and a light sensing device 50 which are separated from each other.
When the distance between the biochemical reaction device 30 in which a biochemical reaction takes place and the light sensing device 50 is denoted by R and a radius of an opening of a light sensor in the light sensing device 50 is denoted by r, the quantity of fluorescent light that is incident on the light sensor, compared to the total quantity (I) of fluorescent light generated as the result of the biochemical reaction, is reduced to I(πr2)/(4πR2) with loss of a lot of light signals.
Therefore, if the ratio of r/R is reduced, the quantity of light that is incident on the light sensor is reduced, whereby the sensitivity is reduced. As the ratio of r/R approaches 1, the sensitivity becomes increased. To maximize the sensitivity, there is the need for embodying the system such that the light sensor and the location of the bio-reaction region are as close to each other as possible.
FIG. 2 is a sectional view of a biochip provided with a light sensor so as to solve the above-mentioned conventional problem.
Referring to FIG. 2, the conventional biochip 100 provided with a light sensor includes a bio-layer 110 and a light sensor layer 120.
The bio-layer 110 includes a reaction region 111 in which a biochemical reaction between a reference sample 111a and a target sample 111b takes place. Furthermore, to make it possible to determine a result of the biochemical reaction, the bio-layer 110 is embodied in such a way that luminescent or fluorescent material remains in the reaction region 111 depending on the degree of reaction.
In the case where luminescent material remains, there is no need for a separate light source because external environment has only to be formed such that the luminescent material itself emits light. However, in the case where fluorescent material remains, a separate light source is required to excite the fluorescent material.
For this, the conventional technique uses the following method: a separate external light source and a fluorescent band-pass filter are provided on an upper end of the optical sensor, or a light emitting device 112 having a reflective plate 113 in a lower portion thereof is installed in the bio-layer 110, so that light emitted from the light emitting device is used to excite the fluorescent material in the bio-layer.
However, in the conventional biochip, while fluorescent signals are created as a result of a biochemical reaction by means of light emitted from the external light source and the internal light emitting device, noise signals of an excitation light that reach thousands to tens of thousands of times more than the fluorescent signals are also generated. Such noise signals enter the light sensor layer, thus making it difficult to correctly detect fluorescent signals resulting from the biochemical reaction.